Androgen-deprivation therapy is the foundation of treatment for men with metastatic prostate cancer (PC) and is now frequently incorporated into multimodality strategies for the curative treatment of locally advanced PC. Unfortunately, the catabolic effects of ADT result in significant morbidity including loss of lean muscle mass, increased fat mass, reduced muscle strength, and lower bone mineral density. In turn, these adverse effects of ADT are linked with functional decline and frailty. Emerging evidence also suggests that men on ADT are at greater risk for cardiovascular disease and the onset of metabolic syndrome. Thus, it is becoming increasingly clear that PC patients endure long and lingering impacts on physical function, health status, and quality of life (QOL) that accompany ADT as a trade-off for more effective cancer control and extended longevity. It has been proposed that lifestyle modification, including change in exercise and dietary behaviors, may offset, or even reverse, the adverse effects that accompany long-term administration of ADT. With a growing clinical focus upon improvements in QOL in cancer survivorship, there is a critical need to identify lifestyle interventions that are effective in offsetting the adverse effets of ADT and minimizing the risk of functional decline and chronic disease in PC patients undergoing treatment. Our long term research goal is to develop innovative and effective lifestyle interventions for the treatment of PC patients undergoing prolonged ADT. However, empirical evidence documenting the efficacy of theory-based, personalized exercise and dietary interventions for improving functional limitations, chronic disease risk factors, and QOL in men on prolonged ADT is limited. Additionally, the pathways through which lifestyle, exercise, and dietary interventions produce improvements in these clinically relevant outcomes have yet to be defined. Our central hypotheses are that: 1) a theory-driven, personalized exercise and dietary intervention will produce superior improvements in functional limitations, body composition, and quality of life relative to a standard of care treatment approach and 2) the intervention effects o functional limitations and QOL will be indirect operating through improvements in self-efficacy beliefs and intermediate disablement process model outcomes. The objective for this current application is to determine the feasibility and preliminary efficacy of an exercise and dietary intervention upon functional, disease, and QOL outcomes in PC patients undergoing ADT. Upon completion of this investigation, the primary positive impact of our findings would be evidence-based scientific verification of the efficacy of lifestyle, exercise, and dietary interventions in prevention and treatment of the adverse effects of prolonged ADT in PC patients. This proposed investigation has the potential to rapidly impact the medical community and their approach to ADT. Should the personalized approach to exercise and dietary modification improve outcomes, we will have the evidence necessary to alter current clinical practice of men on ADT. PUBLIC HEALTH RELEVANCE: It is becoming increasingly clear that men undergoing androgen deprivation therapy (ADT) for metastatic prostate cancer endure long and lingering impacts on physical function, health status, and quality of life as a trade off for more effectiv cancer control and extended longevity. Our overall goal is to develop innovative and effective lifestyle, exercise, and dietary interventions for the treatment of prostate cancer patients undergoing ADT that will prevent and reverse these functional declines and improve their quality of life. This study aims to test the feasibility and preliminary efficacy of a combined exercise an dietary intervention in this population of patients.